Allow configuring GRUB in the nix config

lib/modules/valhalla.nix

@@ -14,6 +14,20 @@
 
     options = {
       valhalla = {
+        boot = {
+          efiMountPoint = mkOption {
+            type = types.str;
+            description = "The mountpoint of the efi partition.";
+            default = "/boot";
+          };
+
+          label = mkOption {
+            type = types.str;
+            description = "The label of the boot entry.";
+            default = "OS";
+          };
+        };
+
         setupUser = {
           name = mkOption {
             type = types.str;

profiles/Generic/config.nix

@@ -1,4 +1,4 @@
-{ ... }:
+{ lib, config, ... }:
   let
     fs = import ../../lib/modules/partition/fs.nix;
   in {
@@ -16,7 +16,7 @@
                 type = "uefi";
                 size = "+1G";
                 format = fs.fat32;
-                mountPoint = "/boot";
+                mountPoint = config.valhalla.boot.efiMountPoint;
               };
 
               Swap = {
@@ -26,6 +26,7 @@
 
               OS = {
                 index = 3;
+                label = lib.mkDefault config.valhalla.boot.label;
                 type = "linux";
                 format = fs.ext4;
                 mountPoint = "/";